Merc 470 Pertronix Ignitor Conversion Problems

[cshirley]

Ok,

I just installed the Pertronix Ignitor to replace the points on my dist. (1978 Merc 470). I followed the directions during install, set the gap with the little plastic slice they give you and went to fire it up and it won't start. It does backfire and spit through the carb and slows or stops cranking at moments like there is a timing problem (too retarded maybe). So I loosened the dist and tried turning it probably 5-10 degrees in each direction trying to see if it would get better but it was the same in both directions with backfiring/spitting and slow crank. I don't know which direction would be advancing and which would be retarding the timing. Also, there was no resistor inline with the coil when I did the install and I have never replaced the coil, it looks pretty stock.

Does anyone know if its common for the timing to be off after installing one of these? Maybe there is something wrong elsewhere even though I followed the instructions.

 

[cheburashka]

Re: Merc 470 Pertronix Ignitor Conversion Problems

There are a lot of threads on this conversion, describing the exact same problems you're looking at. In a nutshell, here's what you're looking at:

These units ALWAYS change the timing. You'll need a timing light to install it correctly. Just moving the distributor 10 degrees with no reference point won't do you any good, and could damage your engine.

There is no inline ballast resistor in your system. Instead, you have a purple resistance wire which needs to be bypassed. The Pertronix instructions explain how to do this, and there are also threads which discuss this.

I think the Pertronix is a good system, but it has to be installed exactly according to the instructions.

 

[buggiedad_67]

Re: Merc 470 Pertronix Ignitor Conversion Problems

by any chance did you have the dis out if you did you may have put it back in 180 out

 

[thumpar]

Re: Merc 470 Pertronix Ignitor Conversion Problems

I installed one of these on my merc 120 last year. I also changed the coil over to internal ballast type also from pertronix. Once done I checked timing and didn't have to touch it. It was still dead on and yes it was checked before. The engine runs fantastic now.

I would make sure the wires are in the correct order. Also when #1 is at TDC is the rotor pointing to #1 wire on the distro?

 

[vtboatr]

Re: Merc 470 Pertronix Ignitor Conversion Problems

I just did this conversion also but used the Sierra kit.

Motor started right up after for me, maybe I was lucky.

Did it run fine prior to the conversion?

I'd pull the cap and set the timing manually to TDC, then check the firing order.

 

[Flyin1500]

Re: Merc 470 Pertronix Ignitor Conversion Problems

Ok,

I just installed the Pertronix Ignitor to replace the points on my dist. (1978 Merc 470). I followed the directions during install, set the gap with the little plastic slice they give you and went to fire it up and it won't start. It does backfire and spit through the carb and slows or stops cranking at moments like there is a timing problem (too retarded maybe). So I loosened the dist and tried turning it probably 5-10 degrees in each direction trying to see if it would get better but it was the same in both directions with backfiring/spitting and slow crank. I don't know which direction would be advancing and which would be retarding the timing. Also, there was no resistor inline with the coil when I did the install and I have never replaced the coil, it looks pretty stock.

Does anyone know if its common for the timing to be off after installing one of these? Maybe there is something wrong elsewhere even though I followed the instructions.

I just did this on my mercruiser 120. Went to fire it up the first time and it did the same thing you are describing. I opened up the rotor cover and realized that I had the rotor on 180 out of whack. Once on properly it fired right up. Check that. Hope it helps!

 

[freddyray21]

Re: Merc 470 Pertronix Ignitor Conversion Problems

been running mine three seasons now and no problems, but I had the same problem at first. They need to be dead on or they won't run. I agree with others the dist maybe 180 out. Check where number one it at.